Instrument-dial illuminator.



E. M. THOMPSON.

INSTRUMENT DIAL ILLUMINATORH APPLICATION FILED JULY 9, 1914.

1,118,969. Patented Dec. 1,19 14,

, llllllillfl UNITED STATES PATENT OFFICE.

ED ARD M. rnomrsou, or BELOIT, WISCONSIN, ASSIGNOR To STEWART-WARNER SPEEIDOMETER CORPORATION, or CHICAGO, ILLINOIS, A CORPORATION or VIRGINIA.

INSTRUMENT-DIAL ILLUMINATOR.

Specification of Letters Patent.

Patented Dec. 1, 1914.

Application filed July 9, 1914. Serial No. 849,891.

' To all whom it may concern minators, of. which the at Beloit, in the county of Rock and State of Wisconsin, have invented new anduseful Improvements in Instrument-Dial Illufollowing is a speci fication, reference being bad to the accompanying drawings, forming a part thereof.

This invention relates to improved means for illuminating an instrument dial to.ren-. der the dial easily readable at night or in dark places.

It consists of the features-and elements described and shown in the drawings as indicated by the claims.

In the drawings, the invention is illustrated as applied to a combined speedometer and odometer designed for use on motor vehicles. j

Figure 1 is a face view of the instrument indicating the relative positions of the indicating elements which are to be read andthe light reflector. Fig. 2 is a View on a larger scale, with parts in section as indicated at line 2.-2 on Fig. 1. Fig. 3 is a detail section, taken as indicated at line 33 on Fig. 2. Fig. 4 is a detail section taken as indicated at line 4& on Fig. 3. Fig. 5 is a rear elevation of the lamp holding plug in position ofuse.

The-instrument illustrated in the drawings consists of a speedometer provided with a rotating dial arranged to appear at a window, A, and trip andtotal odometer trains mounted to show their indicating dials at windows, B and B respectively. All three windows are formed in a single dialor cover-plate, C, and the instrument is pro- D, spaced away from the plate, C, by a short distance.

Vithin the instrument casing, E, and above mechanisms housed thereby there is located an electric light bulb, F, whose light this invention is designed to utilize for illumination of the indicating means in the dial plate, G. The lamp, F, is carried in the usual screw socket, which is mounted in a plug, G, of insulating material arranged to be inserted through an opening in the back Wall, E, of the casing, E. On this wall there is secured a locking plate, E having entrance notches, E designed to admit the pins, G which extend from the body of the plug, G. Just beyond each of the notches,

E. the plate, E to bear against the pin, G as it is rotated in the plate, and the end of this spring, E is bent to form a stop for limiting such rotation; preferably this bent end, E is rounded back slightly from the lane of the spring, E, so as to partially em race the pin, G for more securely retaining it. The insertion of the plug, G, is definitely limited-by its terminal flange, G which is stopped against the back wall, E of the casing. Preferably this flanged end of the plug, G, contains terminal sockets, G adapted to receive lead wires from the source of electric current for energizing the lamp, F. The other end of the plug, G, from which the lamp, F, projects is fitted with a hood, G, the lower half of the lamp and having its inner surface polished or enameled to serve as a reflector for directing the light upward.

Secured to the wall of the casing, E, just above the position of the lamp, F, is a fixed reflector. H, inclined sufficiently to throw the light rays outward past the plane of the dial plate, C, and through the opening, C therein.- Said opening, 0 is provided with surrounding substantially a shield C whose inner surface is also By "irtue of the removable nature of the plug, G, which together with the hood, G, is of such diameter throughout its whole length as to pass freely through the aperture of the locking-plate, the renewal of the lamp, F, when it burns out becomes a very simple matter, not requiring the use of any tools or expert knowledge.

I claim 1. In an instrument having an apertured dial plate, a source of light positioned behind the plane of said plate and means whereby said light serves to illuminate the dial, comprising a hood positioned to intercept the light and directed through the aperture and comprising a reflecting surface at the opposite side of the aperture obliquely across the axis of the aperture,

, for reflecting the light over the dial-plate.

2. In an instrument having a dial plate and a dial glass spaced apart therefrom, the plate having an aperture, a hood over said aperture sloping from the plane of the plate toward the plane of the glass, and a source of light behind the plane of the plate adapted to illuminate the dial by reflection from said hood.

3. In an instrument having an apertured dial plate, an electric lamp positioned behind the plane of said plate and means whereby said lamp may serve to illuminate the dial comprising means for directing the light through the dial-plate, near-the margin thereof, and areflector positioned in front of the dial-plate in the path of the light thus directed through the latter, and at an oblique angle thereto, for directing the light over the dial-plate.

4. In an instrument having an apertured dial plate, an electric lamp positioned behind the plane of said plate and means whereby said lamp may serve to illuminate the dial comprising a hood positioned to intercept the light coming through the aperture and adjusted to reflect such light on to the dial plate together with a reflector at the lamp, and an intermediate reflector positioned to receive the light from the lamp reflector and to deflect such light through the aperture of the dial.

5. In an instrument having a casing and an apertured dial-plate which forms a front closure for the casing, an electric lamp and a plug on which said lamp is mounted; the

casing-wall back of the dial-plate being apertured to receive said plug, the plug with the lamp thereln being adapted to be inserted and withdrawn through such aperand substantially opposite the aperture therein; means for directing the light through the aperture, and a reflector in front of the dial-plate extendingobliquely across the path of the light directed through the aperture, for reflecting the light over the dial-plate. r A

6. In an instrument having a casing and an apertured dial plate, a plug and an electric lamp mounted thereon, the casing being apertured to admit said plug, and means whereby said lamp may serve to illuminate the dial comprising a reflecting hoo'd' carried on the plug over the lamp for directing the light in one general direction, and a relight coming through the aperture of the dial plate and adjusted to reflect such light back on to said plate. I

7. In an instrument having a casing and an apertured dial-plate, a plugand an electric lamp mounted thereon, the back wall of .60 flecting hood positioned to intercept the the casing being apertured to admit said plug; a reflecting hood carried on the plug over the lamp and arranged to project the light toward the topof the casing; a fixed reflector 111 the casing positioned tointercept such light and reflect it through the, aperture of the dial plate, and a hood over said aperture adjusted to reflect said light back against the dial plate.

In testimony whereof, I have hereunto set my hand at Beloit, Rock 00., Wisconsin this 2nd day of July, 1914:.

- EDWARD M. THOMPSON. Witnessesi f H. N. ADAMS, R. A. Enema. 

